﻿////////////////////////////////////////////////////////////////////////////////////////////////////
//
// VSCoverageToEmma - Visual Studio Coverage file to Emma converter
// Copyright (c) Kouji Matsui, All rights reserved.
//
// * Redistribution and use in source and binary forms, with or without modification,
//   are permitted provided that the following conditions are met:
// * Redistributions of source code must retain the above copyright notice,
//   this list of conditions and the following disclaimer.
// * Redistributions in binary form must reproduce the above copyright notice,
//   this list of conditions and the following disclaimer in the documentation
//   and/or other materials provided with the distribution.
//
// THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS "AS IS"
// AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO,
// THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED.
// IN NO EVENT SHALL THE COPYRIGHT HOLDER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT,
// INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES
// (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES;
// LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION)
// HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
// OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE,
// EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
//
////////////////////////////////////////////////////////////////////////////////////////////////////

using System;
using System.Collections;
using System.Collections.Generic;
using System.IO;
using System.Linq;
using System.Reflection;

namespace VSCoverageToEmma
{
	public sealed class VSConverterLoader : IEnumerable<string>
	{
		private Dictionary<string, IVSCoverageConverterFactory> factories_ =
			new Dictionary<string,IVSCoverageConverterFactory>(StringComparer.InvariantCultureIgnoreCase);

		public VSConverterLoader()
		{
		}

		public EventHandler<ExceptionEventArgs> Exception;

		public void Load(string folderPath)
		{
			foreach (var entry in
				from modulePath in
					Directory.GetFiles(folderPath, "VSCoverageToEmma.V*Converter.dll")
				let assembly = LoadFrom(modulePath)
				where assembly != null
				from type in assembly.GetTypes()
				where
					(type.IsClass == true) &&
					(type.IsAbstract == false) &&
					(typeof(IVSCoverageConverterFactory).IsAssignableFrom(type) == true) &&
					(type.GetConstructor(Type.EmptyTypes) != null)
				let factory = CreateFactory(type, modulePath)
				where factory != null
				select factory)
			{
				factories_.Add(entry.Name.ToUpper(), entry);
			}
		}

		private void OnException(Exception ex, string modulePath)
		{
			var exception = this.Exception;
			if (exception != null)
			{
				exception(this, new ExceptionEventArgs(ex, modulePath));
			}
		}

		private Assembly LoadFrom(string modulePath)
		{
			try
			{
				return Assembly.LoadFrom(modulePath);
			}
			catch (Exception ex)
			{
				this.OnException(ex, modulePath);
				return null;
			}
		}

		private IVSCoverageConverterFactory CreateFactory(Type type, string modulePath)
		{
			try
			{
				return (IVSCoverageConverterFactory)Activator.CreateInstance(type);
			}
			catch (Exception ex)
			{
				this.OnException(ex, modulePath);
				return null;
			}
		}

		public IVSCoverageConverter Create(string name, string binariesFolderPath, string symbolsFolderPath)
		{
			var factory = factories_[name.ToUpper()];
			return factory.CreateConverter(binariesFolderPath, symbolsFolderPath);
		}

		public IEnumerator<string> GetEnumerator()
		{
			return factories_.Keys.OrderBy(keyName => keyName).GetEnumerator();
		}

		IEnumerator IEnumerable.GetEnumerator()
		{
			return this.GetEnumerator();
		}
	}
}
